RAY COUNT RATE AND DETECTOR ENERGY SHIFT

Typically, analysis protocols for monazite and/or xenotime call for the same current to be used both for calibration of standards and analysis of unknowns (e g. Scherrer et al. 2000), though adopted current values vary widely (e g.. Finger and Broska 1999, Gratz and Heinrich 1997). However, this approach may cause problems if a standard and unknown generate very different count rates. 

Energy distributions in gas proportional counters— whether gas flow or sealed counters— undergo a noticeable shift to lower energies when X-ray counting rates (and, concomitantly, detector gas ionization rates) increase. The exact origin of this phenome- 

Ca Kai(PET) No interfering peaks in this region of spectmm Kai(PET) No interfering peaks in this region of spectmm 

Y Lai (PET) Lower counts, but separated from P Ka Lai (PET) Y abundant, and separation from P Ka 

La Lai (LIE) No interfering peaks in typical monazite Lal(LIE) Near or below EMP detection limit in xenotime 

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